This invention relates to micro-actuators usable to produce controlled movements.
U.S. Pat. No. 2,896,507 describes an imaging member which includes an elastically deformable layer sandwiched between a pair of electrode plates. In operation, an electrical field is established across the deformable layer, thus causing this layer to deform. The deformation produces relative movement between the electrode plates. U.S. Pat. No. 3,716,359 discloses improved thin flexible metallic layer electrode plates comprising a plurality of different metals such as, for example, gold, indium, aluminum, silver, magnesium, copper, cobalt, iron, chromium, nickel, gallium, cadmium, mercury, and lead. Various techniques for forming the metallic layers on the elastomer layer are described including, for example, by vacuum evaporation. U.S. Pat. No. 4,163,667 describes the use of a composition of titanium and silver for use as the flexible conductive metallic layer electrode plates in imaging members.
U.S. Pat. No. 5,867,301 discloses a phase modulating device wherein the shape of a reflective surface can be modulated by a localized electric field. A grille electrode establishes inhomogeneous electrostatic forces; leading to compressional forces on a deformable media. Thickness variations in the deformable media due to variations in the electric fields lead to optical path length differences in a wavefront which traverses a target. This in turn leads to phase modulations of the wavefront.
It is an object of the present invention to provide a deformable micro-actuator having a grille electrode to establish inhomogeneous electrostatic forces over an elastomer material thereby producing a significant amount of relative movement between the pair of electrode plates in response to the application of a reasonable electrical field.
According to a feature of the present invention, a micro-actuator includes a body of deformable elastomer material having opposed first and second surfaces spaced apart by a predetermined at-rest dimension. A charge mechanism is coupled to one of the opposed surfaces for applying an electrical charge across the body in a first direction. The charge is spatially varied in a second direction substantially normal to the first direction so as to create spatially varied mechanical forces across the body such that body exhibits spatially varied growth in the first direction. A rigid member is associated with the second opposed surface of the body so as to move in the first direction in response to growth of the body.
According to a preferred embodiment of the present invention, the charge mechanism includes a grille electrode connectable to an electrical potential source. An electrically conductive flexible layer is provided on the second surface between the second surface and the rigid member, and is connectable to the electrical potential source so as to induce a force between the flexible layer and the grille electrode upon application of an electrical field. A stationary rigid substrate is provided between the first surface and the grille electrode to establish a rigid mechanical boundary at the first surface.
The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiments presented below.